AIDS, or Acquired Immunodeficiency (ih-MYOO-noe-duh-fish-en-see) Syndrome, is the end stage of infection from the virus known as HIV. You can be HIV-positive for many years before developing AIDS, and show few or no symptoms, yet be able to infect others. This disease impairs your ability to ward off infection, by attacking the cells known as CD4 (C-D-4) or T-cells, which function as an alarm system. When the CD4 cells aren't able to alert your body that an intruder is present, the body can't kill an infection the way it usually would. As HIV progresses, your immune system becomes vulnerable to diseases that are rare in healthy individuals. Having one or more of these defining conditions, along with a low CD4 count, signals the infection has advanced to AIDS. Some diseases commonly associated with AIDS are a type of cancer known as Kaposi's sarcoma (kuh-POE-seez sar-COE-muh), a form of pneumonia called PCP, fungal infections like candidiasis (can-dih-DIE-uh-siss), as well as toxoplasmosis (TOK-so-plaz-MOE-siss), cytomegalovirus (SIGH-toe-MEG-uh-low-vy-rus), and other conditions. Most, if not all, people with HIV infections will someday develop AIDS. Though no cure has yet been discovered, knowledge is advancing constantly, leading to new treatments that can help prevent or delay complications, and may prolong life. For more information, consult an AIDS specialist.